How would I get this 3 tone lighting effect for edges?
You can try this - I'm not sure it will give exactly the look you have, but it's the closest I can think of.
Start by giving your object a Wireframe Modifier (I made mine extra large in the screenshot so it stands out more). Make sure to un-check &quot;replace original&quot; and set the Material offset to 1 - this will allow you to assign a different material to the wireframe than what's on your base object.

Then make sure your object has 2 materials - a base material, and a wireframe material. Make the base material whatever you want, but make the wireframe material look something like this:

Obviously you can adjust the ColorRamp to play with the colors. I've also tried other combinations using a Vector Math node and adding inputs such as a &quot;Facing&quot; from a Layer Weight node, which gives some interesting results, but I'm not sure if it's what you are looking for. Maybe use this idea as a base, and play around until you get something you like. (As a head start, try using a Vector Math node to multiply the Normal Vector by the Pointiness factor.)